Programmed, intermittent boluses versus continuous infusion to the sciatic nerve – a non-inferiority randomized, controlled trial

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Background: Trials comparing programmed, intermittent boluses (PIB) and continuous infusion in catheter-based nerve blocks found no analgesic differences. However, as these trials used equal doses of local anesthetic (LA), the time of action of each bolus was not accounted for. Therefore, the dose-sparing benefits of PIB may have been overlooked. We compared the analgesic effect of boluses administered in intervals resembling the time of action of each bolus with continuous infusion. We hypothesized that PIB provided non-inferior analgesia despite consuming less LA. Methods: Eighty-one patients undergoing fore- and midfoot surgery receiving a catheter-based sciatic nerve block were randomized to ropivacaine 0.2% as PIB of 10 ml every 8th hour or as continuous infusion, 6 ml h−1. All participants could also receive boluses of 10 ml every 4th hour as needed. A non-inferiority randomized controlled design was used. Primary outcome was pain (VAS, 0–100 mm) for 72 h using area under curve (AUC) calculation. We assumed a linear relationship between mean VAS and AUC-VAS and used a non-inferiority margin of VAS = 20 mm, corresponding to AUC-VAS = 1440 mm h. Results: Mean difference in AUC-VAS was −416 mm h (95% CI −1076 to 244; p =.217) between continuous infusion (mean AUC-VAS 1206 mm h) and PIB (mean AUC-VAS 1621 mm h), establishing non-inferiority. Mean total LA consumption was significantly larger for continuous infusion compared to PIB ((468 ml (95% CI 458 to 478) vs. 136 ml (95% CI 123 to 148); p < 0.0001)). Conclusions: PIB provided non-inferior analgesia compared to continuous infusion for 72 postoperative hours despite using significantly less LA.

Original languageEnglish
JournalActa Anaesthesiologica Scandinavica
Volume66
Issue number1
Pages (from-to)114-124
ISSN0001-5172
DOIs
Publication statusPublished - 2022

Bibliographical note

Funding Information:
This trial was funded by Innovation Fund Denmark (grant number 65‐2014‐3) and Nordsjællands Hospital (no grant number).

Funding Information:
This trial was funded by Innovation Fund Denmark (grant number 65-2014-3) and Nordsj?llands Hospital (no grant number). We express our gratitude to the staff of the departments of Anesthesia & Intensive Care and Orthopedic Surgery at Nordsj?llands and Bispebjerg & Frederiksberg Hospitals. A special thanks to Martin Bitsch and Christian Meyhoff who facilitated and assisted trial conduction at Bispebjerg & Frederiksberg Hospital.

Publisher Copyright:
© 2021 Acta Anaesthesiologica Scandinavica Foundation.

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